I've heard that '73 windows are unique, which is the mounting hole relationship between the window and regulator. So the window and regulator have to match. I don't know if the regulators will interchange between the doors.
Yes, I believe the '73 windows are a one year only deal. Regardless, 73+ cars had a totally different regulator mechanism than the 70-72 cars. The replacement glass shows 73/74, but they may have added a hole or something to allow for minor hardware differences.
Demons/Dusters/Dart Sports never had vent windows regardless of the year. Darts/Valiants/Scamps had vent windows 67-72, 73+ did not have vent windows.
To interchange with a '71 you will need a '70-72 regulator mechanism at the least. The door glass is listed as 70-72, obviously that's 71/72 for the demons but it shouldn't matter if its a Duster or a Demon for 70-72. I do know there were some minor changes to the internal hardware within that year range, but I'm not sure if the regulator itself was affected (or it if can be easily modified). The changes were pretty minor.
